1. Field of the Invention
The present invention relates to opening-closing devices used in various electronic devices such as mobile phones and personal computers.
2. Background Art
In recent years, electronic devices such as mobile phones and personal computers are reducing in size and weight, so that more and more such devices are designed to be of the so-called folding type in which the movable housing is opened and closed with respect to the fixed housing. As a result, opening-closing devices used in such electronic devices are also expected to be easier to use and to have a wider variety of opening and closing operations.
An electronic device having a conventional opening-closing device is described as follows by taking a mobile phone shown in FIG. 12 as an example.
FIG. 12 is a perspective view of the conventional mobile phone. The mobile phone includes fixed housing 1 and movable housing 2. Fixed housing 1 is provided on its top surface with operating part 1A having a plurality of arranged keys and with voice input portion 1B such as a microphone.
Movable housing 2 is provided on its surface with display portion 2 such as an LCD and voice output portion 2B such as a speaker. The lower end of movable housing 2 is openably and closably coupled to the upper end of fixed housing 1 via a pair of opening-closing devices 3 and 4.
The pair of opening-closing devices 3 and 4 are each formed of a plurality of cams and springs (unillustrated) and coupled to each other via a coupling member (unillustrated). The pair of opening-closing devices 3 and 4 are installed between fixed housing 1 and movable housing 2, thereby allowing movable housing 2 to be supported openably and closably with respect to fixed housing 1. Thus, fixed and movable housings 1, 2 and opening-closing devices 3, 4 form the electronic device.
When movable housing 2 is closed with respect to fixed housing 1, opening-closing device 3 applies a biasing force to movable housing 2 in the closing direction so as to keep movable housing 2 closed.
Then, when the user opens movable housing 2 with the hand, opening-closing device 3 applies a force to movable housing 2 in the opening direction. As a result, as shown in FIG. 12, movable housing 2 is opened with respect to fixed housing 1 at a predetermined angle of, for example, 160 degrees.
In this situation, if the user pushes switch push button 5 provided on a side surface of fixed housing 1, movable housing 2 is opened wider. This time, opening-closing device 4 applies a biasing force to movable housing 2 in the opening direction, bringing the rear surface of movable housing 2 into contact with the rear surface of fixed housing 1. In other words, movable housing 2 has rotated 360 degrees.
In this manner, the pair of opening-closing devices 3 and 4 are designed so that movable housing 2 is opened by opening-closing device 3 up to around 160 degrees which is suitable for the user to make a phone call and then opened by opening-closing device 4 up to 360 degrees at which operating part 1A and display portion 2A are exposed on the top and bottom, respectively. A conventional art relating to the present invention is shown in Japanese Patent Unexamined Publication No. 2002-171324.
In the aforementioned conventional example, movable housing 2 is opened to and closed from the predetermined angle using opening-closing device 3 and then opened to and closed from the 360 degree angle using opening-closing device 4 by pushing switch push button 5. As a result, the pair of opening-closing devices require a complicated structure due to a large number of components and the time to be installed in an electronic device and to perform the opening and closing operations.